For semiconductor manufacturing processes, various substrate processing apparatuses have been used. For example, in a sputtering process or an etching process for a target processing substrate, such as a semiconductor wafer (hereinafter, referred to as “wafer”) or a glass substrate, a substrate processing apparatus, such as a plasma processing apparatus, has been generally used. In a plasma processing apparatus, process gas introduced into an airtight processing chamber is converted into plasma, and thus the surface of the wafer is plasma processed. If such plasma processing is repeated, a reaction product generated by plasma is attached to the inner wall of the processing chamber, or the parts, such as electrodes arranged in the processing chamber, are worn out, so that the status of the apparatus is slightly changed. Since the status of plasma is also changed according to the status of the apparatus, there is a possibility that the status of the apparatus may influence the processing results, such as the etched shape of a wafer. Therefore, in order to consistently execute stable processing, processing results, including processing characteristics, such as data on the shape of a plasma-processed wafer, and apparatus status, such as the degree of consumption of parts in a processing chamber, should be monitored.
Due thereto, a test wafer, for example, is manufactured in advance, and etching processing is periodically performed on the test wafer, so that the processing characteristics or the status of a substrate processing apparatus may be determined for each etching processing operation on the basis of data on the processing results thereof (for example, the degree of consumption of the test wafer, etc.). According to this example, processing characteristics, or the status of the substrate processing apparatus, can be relatively precisely determined, but there are problems in that, since a large number of test wafers is manufactured, and is processed using a substrate processing apparatus, and respective processing result data must be measured for respective test wafers, a large number of manufacturing processes and a lot of time are required to manufacture test wafers and measure processing results.
In this case, a method of performing plasma processing using a wafer for model creation before a wafer to be manufactured as a product (hereinafter referred to as “wafer for product”) is processed, of creating a modeling equation required to correlate electronic data, which indicates plasma status, with processing result data, such as plasma processing characteristics, of applying electronic data, obtained when the wafer for a product is processed, to the modeling equation, and of predicting plasma processing characteristics, has been proposed (for examples, see Patent References 1 and 2). According to such a prediction method, although the wafer for a product cannot actually be measured, the processing results thereof can be predicted, so that the processing characteristics of the wafer for a product or the status of a substrate processing apparatus can be recognized without requiring a large number of manufacturing processes or consuming a lot of time.
[Patent Reference 1] Japanese Patent Laid-Open publication No. 2003-023001
[Patent Reference 2] Japanese Patent Laid-Open Publication No. 2004-335841
However, since such a conventional prediction method creates a modeling equation using processing result data obtained by measuring a wafer for model creation using a measurement instrument after plasma processing has been performed, there is highly likely that an error is included in the processing result data used for model creation. If a modeling equation is created using the processing result data including the error, the error may also influence prediction results made using the modeling equation, thereby reducing accuracy of prediction.